Energy absorbing blast wall for building structure

ABSTRACT

A wall system protects a building structure from pressure caused by explosive blasts. The wall system includes vertical studs. Outer blast wall panels and inner blast wall panels are secured to the opposing sides of the vertical studs. An upper mounting system is attached to the building structure. An upper mounting system includes a fixed track, a movable mounting track, and an energy absorbing system that flexibly couples the movable mounting track to the fixed track. The upper ends of the vertical studs are attached to movable mounting track. A lower mounting system includes a mounting track that aligns the lower ends of the vertical studs. The wall are filled with an energy absorbing material. The lower ends of the vertical studs are connected to a lower track.

RELATED APPLICATIONS

This application is a continuation-in-part application of pending U.S. patent application Ser. No. 12/336,524, filed on Dec. 16, 2008, which claims the benefit of priority under 35 USC §119(e) to U.S. Provisional Application No. 61/015,195 filed on Dec. 20, 2007. This application is also claims the benefit of priority under 35 USC §119(e) to U.S. Provisional Application No. 61/380,703 filed on Sep. 7, 2010, and to U.S. Provisional Application No. 61/437,628 filed on Jan. 29, 2011. This application incorporates the foregoing nonprovisional application and the foregoing provisional applications by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally in the field of protective wall structures for buildings, and, more particularly, is in the field of blast resistant walls.

2. Description of the Related Art

Current existing blast resistant wall assemblies attempt to resist the extreme forces generated by explosives with massively heavy and very costly components. The wall components endeavor to remain in place when impacted by a blast wave. If the wall components fail, the components are propelled into the interior space of the structure to damage equipment and harm people that the wall components are intended to protect.

SUMMARY OF THE INVENTION

A blast wall assembly and the components described herein form an integrated system that effectively absorbs blast energy. Unlike conventional systems, the components of the blast wall assembly function in a manner similar to highway “crumple zones” by absorbing the energy generated by the sudden impact of a blast wave on the exterior surface of the blast wall. The components of the blast wall assembly flex, move, compress, crush and bend before the full magnitude of the blast load is transmitted via the components to the fasteners used to secure the assembly to the structure. By absorbing the sudden impact of energy, the system greatly reduces the likelihood of component failure and fastener failure. Although the blast wall assembly may incur repairable damage, the blast wall assembly absorbs a substantial portion of the blast energy rather than imploding into the interior space of the structure. Thus, the blast wall assembly greatly enhances the safety of the building structure and the occupants of the building structure.

When a blast pressure wave first impacts an exterior blast board, the exterior blast board resists penetration by objects, such as rocks and shrapnel, which may be hurled against the wall by the blast force. A portion of the energy of the blast wave is absorbed by flexural bending of the exterior blast board. The load applied to the exterior blast board by the blast pressure wave is transferred to vertical wall studs. The exterior blast board also provides lateral bracing for the vertical studs, which helps prevent torsional failure of the light gauge vertical studs. The exterior blast board also serves as a substrate for a variety of exterior finish systems that may be applied to the cementitious wall board forming the outer face of the exterior blast board. Thus, from the outside, the blast wall assembly may be configured to have the cosmetic appearance of a conventional wall.

The light gauge (e.g., 16 gauge) vertical wall studs are flexible. Thus, when the load from the blast pressure wave is applied to the wall studs via the outer blast pane, the wall studs bend and deform and eventually stretch. The magnitude of deformation of the wall studs may exceed the yield strength of the wall studs and cause a portion of the deformation to be permanent. The bending, deformation and stretching of the studs absorbs additional blast energy.

As each vertical wall stud deforms inward away from the blast force, the stud has a tendency to pull out of an upper mounting channel (track) and a lower mounting channel (track) that constrain the upper end and the lower end, respectively, of each stud. An angle clip at the top of each vertical stud and an angle clip at the bottom of each stud resist this pull-out force while simultaneously absorbing blast energy. As the vertical stud deflects inwardly, the chord distance between the top end and the bottom end of the stud shortens. The angle clips have horizontal legs that deform by bending in response to the tensile force that attempts to straighten the angle clips. The deformations of the angle clips absorb additional blast energy.

When the bottom angle clip deforms, the tendency of the bottom angle clip to straighten is resisted by a bottom energy absorbing pad. The bottom energy absorbing pad is compressed vertically as the horizontal leg attempts to pull away from the lower mounting channel. The compression of the bottom energy absorbing pad absorbs additional blast energy. A metal plate laminated to the top of the bottom energy absorbing pad helps prevent the pad from pulling over an anchor bolt at the bottom of the wall and prevents the pad from being crushed by a hexagonal nut that secures the pad to the bottom attachment anchor bolt.

The bottom energy absorbing pads at the bottoms of the wall studs also absorb energy while allowing the entire base of the wall to move inward away from the blast. As described herein, the bottom mounting channel (or track) and the bottom clips include respective slots (or oversized holes) that permit the entire lower portion of the blast wall assembly to move inward away from the blast force until reaching the end of the slot or the boundary of the oversized hole. The bottom energy absorbing pads prevent the wall from moving too quickly and applying a shock load to the lower anchor bolts. When the bottom energy absorbing pads compress under load, the pads create a more gradual (cushioned) increase in the load to the wall anchors. Thus, the bottom energy absorbing pads help preserve the integrity of the critical attachment of the wall to the building structure.

An upper mounting system and an upper energy absorbing assembly at the top of the blast wall assembly absorb blast energy and resist destructive movement caused by the blast energy. The upper mounting system and the upper energy absorbing assembly also permit the floor above the blast wall assembly to deflect vertically in response to changing live loads to the floor above the wall, the floor below the wall or both. The floating configuration of the upper mounting allows deflections to occur without transferring axial loads (e.g., bearing loads) to the wall. The blast wall assembly disclosed herein can be used as either a non-bearing partition wall or as a curtain wall.

When a top angle clip deforms, the tendency of the clip to straighten is reduced by the bending of a horizontal flange stud that spans the distance between adjacent upper mounting systems. The tensile force caused by a blast causes the angle clip to bend (e.g., straighten) and induces weak axis bending in the horizontal flange stud. The horizontal flange stud also provides an engagement between the vertical wall studs and an upper blast track. In particular, the outer surfaces of the vertical walls of the horizontal flange stud ride may float up or down within the cavity formed by the upper blast track. The floating engagement between the horizontal stud and the upper blast track is configured to reduce the effect of the blast forces. As described herein, the top angle clip and the horizontal flange stud are nested so that the side walls of the horizontal flange stud are unobstructed within the upper blast track to thereby accommodate vertical movement between the floor above and the wall below. Additional blast energy is absorbed by bending of the horizontal stud flange and bending of the flange of the upper blast track on the side of the wall opposite the blast. Both components bend in a direction normal to the plane of the wall.

Lateral movement of the blast wall assembly in a direction normal to the wall plane is primarily resisted by bending of a down-turned flange of the upper blast track. As each vertical stud bends, the chord distance between the upper and lower ends of the vertical stud shortens as discussed above. A spring or other elastic member in the upper energy absorption assembly compresses to absorb blast energy. Once the spring in the energy absorbing assembly is fully compressed, a threaded steel rod in the assembly transmits tensile loads to the upper blast track through the anchor wedge washer. As the wall deforms inward, the threaded rod pivots to transfer tensile load and shear load to the upper blast track, which causes the upper blast track to deform in the vicinity of the wedge washer. The deformation of the upper blast track absorbs more blast energy.

Once the blast load is transferred to the upper blast track by bending the outer wall (flange of the upper blast track) and by the upper energy absorption assembly, the transferred load is transferred to the building structure by way of an upper anchor bolt embedded in a header. The force transferred to the upper anchor bolt is cushioned by the deformation of a trapezoidal channel in the upper blast track and by the vertical flange and weak axis bending of a U-shaped blast track anchor channel. The shape of the blast track in combination with the blast track anchor channel results in a more gradual transfer of forces to the top connection, which helps preserve the integrity of the top connection and of the blast wall assembly.

The blast wall assembly further comprises an interior blast board. Each panel of the interior blast board comprises a layer of metal and an interior finish wall board to form a generally rectangular sheet. In a preferred embodiment, the interior blast board is fabricated with a metal flange extending along one of the long edges. The long edges are oriented horizontally in the preferred embodiments. The metal flange allows the interior sheathing to be spliced to the adjacent sheathing (the inner blast panel immediately above). The splice effectively connects the upper and lower sheathing boards to form a continuous protective curtain reaching from the top to the bottom of the wall. If one or more sheets become dislodged, the dislodged sheets remain in place on the wall and pose no hazard to the building occupants. Preferably, the sheets are positioned on the wall with the locations of the splices staggered so that the splices do not coincide with the utility punch outs in the vertical studs of the wall. Thus, the interior blast board reinforces the wall and helps prevent stud failure at the utility punch-outs. Furthermore, the metal lined interior blast boards provide torsional restraint for the vertical studs to effectively prevent torsional failure of the vertical studs. In alternative embodiments, the interior blast board may be oriented vertically, and may be constructed without the extended metal flanges.

In accordance with another embodiment disclosed herein, a wall system for protecting a building structure from pressure caused by explosive blasts, comprises a plurality of vertical studs having respective upper ends and lower ends. At least one outer blast wall panel is secured to the vertical studs to form an outer wall of the wall system. At least one inner blast wall panel is secured to the vertical studs to form an inner wall of the wall system. An upper mounting system is attached to the building structure, and the upper ends of the vertical studs are attached to the upper mounting system. A lower mounting system is attached to the building structure, and the lower ends of the vertical studs attached to the lower mounting system. At least one cavity is formed between the at least one outer blast wall and the at least one inner blast wall, and an energy absorbing material substantially fills the at least one cavity.

In certain embodiments of the wall system, the energy absorbing material comprises expanded polystyrene foam.

In certain embodiments of the wall system, each vertical stud extends from the at least one outer blast wall panel to the at least one inner wall panel.

In other embodiments of the wall system, each vertical stud is positioned to be attached to only the at least one inner blast wall panel or to only the at least one outer blast wall panel. For example, the vertical stud attached to the at least one inner blast wall panel comprises a U-channel stud having a web and a respective flange at each edge of the web; and the at least one inner blast wall panel is connected to the web of the vertical stud with the flange at each edge of the web extending into the energy absorbing material in the cavity. Similarly, the vertical stud attached to the at least one outer blast wall panel comprises a U-channel stud having a web and a respective flange at each edge of the web; and the at least one outer blast wall panel is connected to the web of the vertical stud with the flange at each edge of the web extending into the energy absorbing material in the cavity.

Alternatively, the vertical stud attached to the at least one inner blast wall panel comprises a C-stud having a web, a respective flange at each edge of the web, and a respective lip perpendicular to each flange, and the at least one inner blast wall panel is connected to the web of the vertical stud with the flange at each edge of the web extending into the energy absorbing material in the cavity, and with each lip embedded in the energy absorbing material. Similarly, the vertical stud attached to the at least one outer blast wall panel comprises a C-stud having a web, a respective flange at each edge of the web, and a respective lip perpendicular to each flange; and the at least one outer blast wall panel is connected to the web of the vertical stud with the flange at each edge of the web extending into the energy absorbing material in the cavity, and with each lip embedded in the energy absorbing material.

In accordance with certain embodiments, a wall system for protecting a building structure from pressure caused by explosive blasts comprises an inner blast wall panel having a generally rectangular metal sheet and an interior wall board laminated to the metal sheet. The inner blast wall panel is secured to vertical studs with the metal sheet positioned against the vertical studs and with the interior wall board facing away from the vertical studs. The wall system further includes an outer blast wall panel having a generally rectangular metal sheet and an exterior wall board laminated to the metal sheet. The outer blast wall panel is secured to vertical studs with the metal sheet positioned against the vertical studs and with the exterior wall board facing away from the vertical studs. An energy absorbing material is positioned between the inner blast panel and the outer blast panel. In certain embodiments, the wall system is mounted between an upper header and a lower footer. In other embodiments, the wall system is mounted to an outer face of a structure to span between two floors of the structure as a curtain wall. In a particular configuration of the wall system, the inner blast panel and the outer blast panel are secured to opposing flanges of studs that extend through the energy absorbing material between the inner blast panel and the outer blast panel. In another configuration of the wall system, the inner blast panel is secured to a first set of studs, and the outer blast panel is secured to a second set of studs, wherein the first set of a studs and the second set of studs separated by the energy absorbing material.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and other aspects of this disclosure are described in detail below in connection with the accompanying drawing figures in which:

FIG. 1 illustrates a perspective view of a blast wall installed between an upper concrete header and a lower concrete footer with respective portions of the header and footer removed to show the mounting anchor bolts;

FIG. 2 illustrates an enlarged cross-sectional elevational view of a portion of the upper concrete header, the mounting tracks, the upper ends of two vertical studs and an energy absorption assembly between the vertical studs viewed in the direction of the lines 2-2 in FIG. 1;

FIG. 3 illustrates an enlarged cross-sectional elevational view of a portion of the lower concrete footer, the bottom track, the lower ends of two vertical studs and the energy absorption pad viewed in the direction of the lines 3-3 in FIG. 1;

FIG. 4 illustrates an elevational cross-sectional end view of the blast wall of FIG. 1 in the direction of the lines 4-4 in FIG. 1 that shows the attachment structures at the top and bottom portions of an exemplary vertical stud and which further shows the structure of the inner blast panel (to the left in FIG. 4) and the outer blast panel (to the right in FIG. 4);

FIG. 5 illustrates an enlarged cross-sectional elevational end view of the top portion of the vertical wall stud of FIG. 4 bounded by the circular area 5 in FIG. 4;

FIG. 6 illustrates an enlarged cross-sectional elevational end view of the bottom portion of the vertical wall stud of FIG. 4 bounded by the circular area 6 in FIG. 4;

FIG. 7 illustrates an enlarged cross-sectional elevational end view in the direction of the lines 7-7 in FIG. 1 that shows the energy absorption system that couples the upper blast track to the floating blast wall;

FIG. 8 illustrates an enlarged cross-sectional view of a portion of the overlap of an upper inner blast panel with respect to a tab extending upward from a lower inner blast panel which is bounded by the circular area 8 in FIG. 4;

FIG. 9 illustrates an enlarged cross-sectional view in the direction of the lines 9-9 in FIG. 1 to show the mounting of the inner blast panel and the outer blast panel to the upper mounting channel (track);

FIG. 10 illustrates a perspective view of the blast track anchor channel mounted to the upper anchor bolt;

FIG. 11 illustrates an end elevation view of the blast track anchor channel and the upper anchor bolt of FIG. 10;

FIG. 12 illustrates an enlarged perspective view of the blast energy absorption assembly of FIG. 7;

FIG. 13 illustrates an end elevation view of the blast energy absorption assembly of FIG. 12;

FIG. 14 illustrates a perspective view of the upper stud attachment clip of FIG. 5;

FIG. 15 illustrates a perspective view of the lower stud attachment clip of FIG. 6;

FIG. 16 illustrates an exploded perspective view of the elastomer block and the metal plate of the energy absorption pad of FIG. 6

FIG. 17 illustrates a perspective view of the assembled energy absorption pad of FIG. 6;

FIG. 18 illustrates a perspective view of the upper blast track of FIG. 1 to show the holes for mounting the upper blast track to the upper concrete header and showing the holes for mounting the energy absorption assembly to the blast track;

FIG. 19 illustrates an end elevational view of the upper blast track of FIG. 18 to show a preferred cross section for the upper blast track;

FIG. 20 illustrates a perspective view of the upper horizontal stud of FIG. 1 mounted to the upper mounting channel (track) of FIG. 1 to show the holes for mounting the energy absorption assembly and to show the pilot holes for mounting the upper stud attachment clip of FIG. 14;

FIG. 21 illustrates an end elevational view of the joined upper horizontal stud and upper channel of FIG. 20 to show preferred cross sections for the joined components;

FIG. 22 illustrates a perspective view of the lower mounting channel (track) of FIG. 1 to show the slotted holes for attaching the lower mounting channel to the lower concrete footer;

FIG. 23 illustrates an end elevational view of the lower mounting channel of FIG. 22 to show a preferred cross section for the lower mounting channel;

FIG. 24 illustrates a perspective view of portion of a wall section in accordance with a further embodiment of an energy absorbing blast wall in which the cavity between inner and outer blast panels mounted on C-studs is substantially filled with an energy absorbing material, and in which the wall section is coupled to the building by the energy absorbing track assemblies;

FIG. 25 illustrates an enlarged cross-sectional plan view of the portion of the wall in FIG. 24 viewed in the direction of the lines 25-25 in FIG. 24;

FIG. 26 illustrates a perspective view of portion of a wall section in accordance with FIG. 24 in which the wall section is coupled to the building by a fixed track assembly;

FIG. 27 illustrates an enlarged cross-sectional plan view of the portion of the wall in FIG. 26 viewed in the direction of the lines 27-27 in FIG. 26;

FIG. 28 illustrates a perspective view of portion of a wall section in accordance with a further embodiment of an energy absorbing blast wall in which the cavity between inner and outer blast panels mounted on the webs of respective sets of U-channel studs is substantially filled with an energy absorbing material, and in which the wall section is coupled to the building by the energy absorbing track assemblies;

FIG. 29 illustrates an enlarged cross-sectional plan view of the portion of the wall in FIG. 28 viewed in the direction of the lines 29-29 in FIG. 28;

FIG. 30 illustrates a perspective view of portion of a wall section in accordance with FIG. 28 in which the wall section is coupled to the building by a fixed track assembly;

FIG. 31 illustrates an enlarged cross-sectional plan view of the portion of the wall in FIG. 30 viewed in the direction of the lines 31-31 in FIG. 30;

FIG. 32 illustrates a perspective view of portion of a wall section in accordance with a further embodiment of an energy absorbing blast wall in which the cavity between inner and outer blast panels mounted on the webs of respective sets of C-studs is substantially filled with an energy absorbing material, and in which the wall section is coupled to the building by the energy absorbing track assemblies;

FIG. 33 illustrates an enlarged cross-sectional plan view of the portion of the wall in FIG. 32 viewed in the direction of the lines 33-33 in FIG. 32;

FIG. 34 illustrates a perspective view of portion of a wall section in accordance with FIG. 32 in which the wall section is coupled to the building by a fixed track assembly;

FIG. 35 illustrates an enlarged cross-sectional plan view of the portion of the wall in FIG. 34 viewed in the direction of the lines 35-35 in FIG. 34;

FIG. 36 illustrates a perspective view of the wall section of FIG. 34 mounted as part of a curtain wall;

FIG. 37 illustrates an enlarged cross-sectional plan view of the portion of the wall corresponding to the cross-sectional plan view of FIGS. 33 and 35 wherein the C-studs are replaced with modified studs;

FIG. 38 illustrates an enlarged cross-sectional plan view of the wall section corresponding to the wall section of FIG. 37 but with the studs coupled to the inner blast panels aligned with the studs coupled to the outer blast panels;

FIG. 39 illustrates a perspective view of a blast wall similar to the blast wall of FIG. 1 modified with a lower track (channel) having integral tabs for connecting to the vertical studs, wherein portions of the inner and outer blast panels are removed to show the lower end of one of the vertical studs;

FIG. 40 illustrates an enlarged perspective view of the bottom portion of the blast wall of FIG. 39 bounded by the circular area 40 in FIG. 39;

FIG. 41 illustrates a perspective view of the initial construction of the lower channel of FIGS. 39 and 40 showing the generally U-shaped slot and the pilot hole formed in the webbing of the lower track at intervals corresponding to the stud spacing;

FIG. 42 illustrates an enlarged perspective view of the portion of the lower track of FIG. 41 bounded by the area 42 in FIG. 41;

FIG. 43 illustrates a perspective view of the second stage of construction of the lower track of FIG. 41 showing the tabs bent upward from the webbing to a position substantially perpendicular to the webbing;

FIG. 44 illustrates an enlarged perspective view of the portion of the lower track of FIG. 43 bounded by the area 44 in FIG. 43;

FIG. 45 illustrates a perspective view of a blast wall similar to the blast wall of FIG. 1 that mounts the lower stud attachment clip directly to the webbing of the lower track and that includes a plate to secure the webbing of the lower track to a mounting anchor bolt, wherein portions of the inner and outer blast panels are removed to show the lower end of one of the vertical studs; and

FIG. 46 illustrates an enlarged perspective view of the bottom portion of the blast wall of FIG. 45 bounded by the circular area 46 in FIG. 45.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates a perspective view of a blast wall 100. The blast wall comprises a blast wall assembly 110 installed between an upper header 112 and a lower footer 114. In the illustrated embodiment, the header and the footer comprise concrete; however, the header, the footer or both may comprise other suitable materials. In the illustrated embodiment, the blast wall assembly is secured to the header and the footer by a plurality of upper anchor bolts 120 (one of which is shown in the broken section of the header) and a plurality of lower anchor bolts 122 (one of which is shown in the broken section of the footer). In the illustrated embodiment, the upper anchor bolts are advantageously spaced apart by approximately 24 inches and the lower anchor bolts are advantageously spaced apart by 16 inches. In other configurations, the distances between the anchor bolts may be different.

As further shown in FIG. 1, the blast wall assembly 110 comprises a plurality of inner blast panels (interior blast boards) 130 and a plurality of outer blast panels (exterior blast boards) 132 mounted on a plurality of vertical wall studs 134. The vertical studs advantageously comprise conventional light gauge metal studs having a C-shaped cross section. For example, in the illustrated embodiment, each metal stud has a main body portion having an outside width of approximately 4 inches, has opposing side walls that extend approximately 2 inches perpendicular to the main body portion, and has flanges that extend inwardly perpendicular to the side walls for approximately ½ inch. In one embodiment, each metal stud comprises 16 gauge steel having a thickness of approximately 1/16 inch. The width of the main body of each stud may be increased to increase the overall thickness of the blast wall assembly. The vertical studs are advantageously spaced apart by a conventional distance. In the illustrated embodiment, the vertical studs are spaced apart by approximately 16 inches. For additional wall strength, the vertical studs may be spaced apart by 12 inches, for example.

As further shown in FIG. 1, the upper end of each vertical stud 134 is mounted to an upper mounting track (channel) 140, which is advantageously a modified conventional mounting channel for a metal-framed building. For example, as shown in FIGS. 20 and 21, the upper channel advantageously comprises 16 gauge steel formed into a generally U-shaped profile having a base portion with an inner width of approximately 4 inches between two perpendicular side walls. In particular, the inner width of the upper channel is sized to accommodate the outer width of each vertical stud. Accordingly, for thicker walls having vertical studs with a greater base size, the inner width of the base of the upper channel is increased accordingly. In the illustrated embodiment, the side walls have lengths of approximately 1.5 inches. The open face of the U-shaped profile is positioned fastened downwardly to receive the upper end of each vertical stud.

Unlike an upper channel in a conventional metal-framed wall structure, the upper mounting channel 140 in FIG. 1 is not fixedly attached to the upper header 112. Rather, as described below in more detail, the upper channel is mounted to an upper horizontal stud 142, which advantageously comprises a conventional C-shaped framing stud positioned horizontally rather than vertically. In the illustrated embodiment, the horizontal stud has a profile and dimensions that correspond to the profile and dimensions of the vertical studs 134 as described above. The open portion of the horizontal stud faces upwardly so that the back of the horizontal stud rests on the back of the downwardly facing upper mounting channel. As described below, the horizontal stud and the upper mounting channel are fastened together and are shown as a unit in FIGS. 20 and 21. The width of the horizontal stud in the illustrated embodiment is 4 inches in the illustrated embodiment. The width of the horizontal stud is increased to correspond to the width of the vertical stud 134 if the thickness of the blast wall assembly 110 is increased.

As further described in more detail below, the horizontal stud 142 fits within a downwardly facing opening in a generally M-shaped upper blast track 144, which is shown in more detail in FIGS. 18 and 19. As illustrated, the upper blast track does not have a flat base. Rather, a central portion of the base is depressed to form a generally trapezoidal depression 146. The upper blast track is secured to the upper header 112 by the upper anchor bolts 120 by an upper mounting system described below. The horizontal stud and the upper mounting channel are not fixedly attached to the upper blast track and are free to move up and down as a unit within the upper blast track. Accordingly, the engagement between the horizontal stud and the upper blast track provide a floating mounting structure.

In the illustrated embodiment, the upper blast track 144 has an inside width of approximately 4 inches to accommodate the outside width of the upper horizontal stud 142. The inside width is increased to accommodate a wider horizontal stud if the thickness of the blast wall assembly 110 is increased. The generally trapezoidal depression 146 maintains the same size and shape even if the overall width of the upper blast track is increased for a thicker blast wall assembly. In particular, the depression causes the base of the upper blast track to protrude approximately 0.676 into the inner cavity of the upper blast track. The protrusion has a width within the cavity of approximately of approximately 2.434 inches.

As further shown in FIG. 1, the lower end of each vertical stud 134 is mounted to a lower mounting track (channel) 150, which is also advantageously a modified conventional mounting channel for a metal-framed building having a structure and dimensions similar to the upper channel 140. Unlike the lower channel in a conventional metal-framed wall structure, the lower channel in FIG. 1 is not fixedly attached to the lower header 114. Rather, as described below in more detail, the lower channel is mounted to the lower header in a manner that allows the lower channel to move laterally. Also, the lower end of the vertical stud is mounted within the lower channel to allow the vertical stud to move by a limited amount within the lower channel.

In the illustrated embodiment, each of the inner blast panels 130 and the outer blast panels 132 is generally rectangular and has a length greater than the width. The blast panels are mounted on the respective insides and outsides of the vertical studs with the longer dimension mounted horizontally as shown to reduce the number of vertical seams in the finished panels. Thus, each of the inner wall and the outer wall has at least two courses (rows) of panels. For example, the blast wall assembly 110 illustrated in FIG. 1 has a height of approximately 8 feet and comprises two rows of panels. A twelve-foot wall advantageously comprises three rows of panels. As further illustrated in FIG. 1, in preferred embodiments, the vertical seams in adjacent rows are staggered to reduce the overall length of a continuous vertical seam. In alternative embodiments, either the inner blast panels or the outer blast panels or both the inner blast panels and the outer blast panels are mounted on the respective insides and outsides of the vertical studs with the long dimension oriented vertically.

As shown in more detail in FIGS. 8 and 9, for example, each inner blast panel 130 advantageously comprises a metal sheet 160 bonded to an interior wall board 162 using a suitable adhesive, such as, for example, an epoxy or a glue. The adhesive is cured (e.g., dried) while applying pressure to the two layers of materials to form the laminated inner blast panel. The inner blast panel is advantageously constructed in accordance with the technique described in U.S. Pat. No. 5,768,841, which is incorporated by reference herein. In the illustrated embodiment, the steel sheet advantageously comprises galvanized steel. The steel sheet advantageously has a thickness that ranges from approximately 0.0285 inch (22 gauge) to approximately 0.0713 inch (14 gauge). In the illustrated embodiment, the steel sheet is advantageously 20 gauge. The inner blast panels are mounted against the metal studs 134 with the metal sheet against the metal studs.

In the illustrated embodiment, the interior wall board 162 has a conventional rectangular configuration with a width of approximately 4 feet and has a length of approximately 8 feet; however, the interior wall board may have other dimensions. For example, in other embodiments, the interior wall board may have a length of approximately 12 feet to reduce the number of seams between inner blast panels. In particular embodiments, the wall board comprises a highly mold-resistant interior gypsum board, such as, for example, ⅝ inch DensArmor Plus® paperless interior drywall, which is commercially available from Georgia-Pacific Building Products of Atlanta, Ga. Other suitable interior wall board materials may be advantageously used.

In the preferred embodiment shown in FIG. 1, the metal sheet 160 has substantially the same length as the interior wall board 162. The metal sheet may also have substantially the same width as the interior wall board; however, in the illustrated embodiment, the metal sheets of at least the inner blast panels 130 for the lower row of panels preferably has a greater width. In particular, as shown in FIG. 8, a portion of the metal sheet extends beyond one of the longer edges of the wall board to form an exposed metal tab 164 having a width of approximately 1¼ inches. As further shown in FIG. 8, a panel in the upper row of panels is positioned over the metal tabs of the panel in the next lower row of panels. Accordingly, when the inner blast panels are secured to the metal studs, the metal sheets form a continuous vertical diaphragm across against the metal studs. The metal tab is not needed for the uppermost row of inner blast panels. The metal tab may be removed. Alternatively, the inner blast panels may be provided without tabs for installation on the uppermost rows.

As shown in FIG. 9, for example, the outer blast panel 132 has a configuration similar to the configuration of the inner blast panel 130. The outer blast wall advantageously comprises a metal sheet 170 bonded to an exterior wall board 172 using a suitable adhesive, such as, for example, an epoxy or a glue. The adhesive is cured (e.g., dried) while applying pressure to the two layers of materials to form the laminated inner blast panel. The outer blast panel is advantageously constructed in accordance with the technique described in U.S. Pat. No. 5,768,841, which is incorporated by reference herein. The steel sheet advantageously has a thickness that ranges from approximately 0.0285 inch (22 gauge) to approximately 0.0713 inch (14 gauge). In the illustrated embodiment, the steel sheet is advantageously 14 gauge. In the illustrated embodiment, the steel sheet advantageously comprises 14 gauge (approximately 0.071 inch thick) galvanized steel. The outer blast panels are mounted against the metal studs 134 with the metal sheet against the metal studs.

In the illustrated embodiment, the exterior wall board 172 has a conventional rectangular configuration with a width of approximately 4 feet and has a length of approximately 8 feet; however, the exterior wall board may have other dimensions. For example, in other embodiments, the exterior wall board may have a length of approximately 12 feet to reduce the number of seams between outer blast panels. In particular embodiments, the exterior wall board comprises a highly mold-resistant exterior cement board, such as, for example, ⅝ inch Durock® brand cement board, which is commercially available from USG Corporation of Chicago, Ill. Other suitable exterior wall board materials may be advantageously used.

In the illustrated embodiment, the metal sheet 170 of the outer blast panel 132 advantageously has dimensions generally corresponding to the dimensions of the exterior wall board 172; however, the metal sheet may be wider to provide a tab (not shown) similar to the tab 164 described above for the inner blast panel 130.

As shown in FIGS. 8 and 9, each inner blast panel 130 is secured to the plurality of vertical studs 134 by a plurality of inner wall fasteners 180. For example, in the illustrated embodiment, the inner wall fasteners advantageously comprise No. 8 Senco® Duraspin screws commercially available from Senco Products of Cincinnati, Ohio. The inner wall fasteners are spaced apart by a selected distance along the vertical studs. For example, in the illustrated embodiment, the inner fasteners are spaced apart by a center-to-center distance of approximately 6 inches. Each inner blast panel in the upper row is also advantageously secured to the upper channel 140 by a plurality of the selected fasteners, which are also spaced apart by a suitable distance (e.g., 6 inches). Furthermore, the lower portion of each inner blast panel in the upper row is fastened to the tab 164 of the inner blast panels which the upper panel overlaps by inserting fasteners in the areas spanning between adjacent vertical studs. Each inner wall fastener has a flat head and is driven into the inner blast panel until the head of the fastener is flush with the exposed surface of the inner blast panel. Thus, when the structure of the blast wall assembly 110 is completed, the exposed surfaces of the inner blast panels may be finished in a conventional manner so that the wall has the appearance of a conventional wall.

As shown in FIG. 9, each outer blast panel 132 is secured to the side walls of a plurality of vertical studs 134 by a plurality of outer wall fasteners 190. For example, in the illustrated embodiment, the outer wall fasteners advantageously comprise a 3/16 inch or ¼ inch Kwik-Con concrete screws commercially available from Hilti, Inc. of Tulsa, Okla. The outer wall fasteners are spaced apart by a selected distance along the vertical studs. For example, in the illustrated embodiment, the outer wall fasteners are spaced apart by a center-to-center distance of approximately 4 inches. Each outer blast panel in the upper row is also advantageously secured to the upper channel 140 by a plurality of the selected fasteners, which are also spaced apart by a suitable distance (e.g., 6 inches). If the lower outer blast panels include tabs (not shown), the lower portion of each outer blast panel in the upper row is fastened to the tab of the outer blast panels which the upper panel overlaps. Each outer wall fastener has a flat head and is driven into the outer wall panel until the head of the fastener is flush with the exposed surface of the outer wall panel.

FIG. 2 illustrates an enlarged cross-sectional elevational view of a portion of the upper concrete header 112, the upper blast track 144, the horizontal stud 142, the upper mounting channel 140, and the upper ends of two vertical studs 134 viewed in the direction of the lines 2-2 in FIG. 1.

FIG. 2 further illustrates an upper mounting system 200 that secures the upper blast track 144 to an upper anchor bolt 120. The mounting system is shown in more detail in a cross-sectional end view in FIG. 5 and is also shown in a perspective view in FIG. 10 and an elevational view in FIG. 11. As illustrated, the upper mounting system comprises a generally U-shaped blast track anchor channel 202. The anchor channel advantageously comprises 14 gauge steel having a thickness of approximately 0.071 inch. The base of the anchor channel has an inside width of approximately 2.434 inch, which is selected to be substantially the same as outside width of the trapezoidal depressed portion 146. Each leg of the anchor channel has an inside length of approximately 0.676 inch, which corresponds to the height of the protrusion within the cavity of the upper blast track. The base of the anchor channel has a circular hole 204 formed approximately in the middle. The hole has a diameter of approximately 9/16 inch to accommodate the outer diameter of the upper mounting anchor 120.

As shown in FIG. 18, the upper blast track 144 has a first plurality of mounting holes 206 substantially along a center line through the depressed portion 146. Each of the first plurality of mounting holes has a diameter corresponding to the diameter of the hole in the blast track anchor channel 202. The first plurality of mounting holes in the upper blast track are spaced apart by approximately 24 inches to correspond to the spacing of the upper anchor bolts in the upper header 112. As shown in FIG. 5 for one blast track anchor channel and one upper anchor bolt, the upper blast track is positioned with the upper anchor bolt positioned through a hole in the blast track, and the blast track anchor channel is positioned with the open portion of the U shape facing upward so that when the blast track anchor channel is positioned with the upper anchor bolt through the hole, the blast track anchor channel is positioned with the two legs surrounding the protruding portion of the depressed portion of the upper blast track and with the inside of the base of the blast track anchor channel positioned against the inner wall of the depressed portion.

The upper mounting system 200 further includes a standard washer 206 and a hex nut 208. The hex nut engages the threaded end of the upper anchor bolt 120 and secures the blast track anchor channel 202 to the upper anchor bolt. The legs of the blast track anchor channel are substantially perpendicular to the base of the blast track anchor channel. The blast track anchor channel resists compression when the nut is tightened onto the upper anchor bolt. In the absence of the blast track anchor channel, the trapezoidal shape of the upper blast track 144 would tend to flatten out as the nut is tightened. Thus, the blast track anchor channel reinforces the upper blast track and also prevents the upper blast track from deforming.

FIG. 2 further illustrates an upper energy absorption assembly 220 that flexibly couples the horizontal stud 142 and the upper mounting channel 140 to the upper blast track 144. The upper energy absorption assembly is shown in more detail in a cross-sectional end view in FIG. 7 and is also shown in a perspective view in FIG. 12 and an elevational view in FIG. 13.

The upper energy absorption assembly 220 comprises a threaded rod 222 having a length of approximately 8 inches. The threaded rod may be threaded for the entire length, or, as illustrated in FIGS. 12 and 13, may be threaded only at the two ends. The threads at the upper end of the threaded rod engage the threads in a threaded hole 226 in an anchor wedge washer 224. As shown in FIG. 7, the anchor wedge has a generally trapezoidal profile selected to conform to the shape and size of the depressed portion 146 of the outer wall of the base of the upper blast track 144. The upper threaded portion of the threaded rod passes through one of a second plurality of holes 230 along the centerline of the depressed portion of the upper blast track. The second plurality of holes are shown in FIG. 18. In the illustrated embodiment, the second plurality of holes are spaced apart by 16 inches to correspond to the spacing of the vertical studs 134 so that an energy absorption assembly may be positioned in the space between each pair of adjacent vertical studs. In alternative embodiments, the energy absorption assemblies may be positioned only in every other space between the vertical studs (e.g., every 32 inches). In further alternative embodiments, the energy absorption assemblies may be positioned in every third space between the vertical studs (e.g., every 48 inches). The upper blast track may be formed with only the second plurality of holes needed for the selected alternative embodiment or may be formed with holes every 16 inches as shown. Preferably, the second plurality of holes are spaced apart from the first plurality of holes 206 so that the adjacent holes are no closer than 4 inches.

As shown in FIG. 7, the threaded rod 222 passes through the base of the horizontal stud 142 and through the base of the upper mounting channel 140. As illustrated in FIG. 20, the horizontal stud and the upper mounting channel include a plurality of clearance holes 232 that are spaced apart by the same distance as the second plurality of holes 230 of the upper blast track 144 (e.g., 16 inches in the illustrated embodiment). In FIG. 20, a portion of the side wall is broken away to show two of the clearance holes. The other clearance holes are hidden by the unbroken portion of the side wall.

As further illustrated in FIGS. 7, 12 and 13, the upper energy absorption assembly 220 further comprises a bearing washer 234 that comprises a generally square metal plate having sides of approximately 3 inches and having a thickness of approximately ⅛ inch. The bearing washer has a clearance hole 236 positioned substantially in the center of the square shape. For example, the clearance hole advantageously has a diameter of approximately 9/16 inch to accommodate the threaded rod 222.

When the upper energy absorption assembly 220 is positioned on the upper blast track 144, the bearing washer 234 is mounted below the base of the upper mounting track 140. The bearing washer applies pressure to the upper mounting track. The pressure is provided by a compression spring 238 that is positioned around the threaded rod between the bearing washer and a spring cap washer 240. The spring cap washer has a central clearance hole 242 that accommodates the lower end of the threaded rod 222. The spring cap washer comprises a 2-inch diameter steel plate having a thickness of approximately 1/16 inch. The spring cap washer is secured to the lower end of the threaded rod by a standard washer 244 and a hexagonal nut 246.

In the illustrated embodiment, the compression spring 238 advantageously comprises a ⅜ inch diameter steel wire formed as a helical spring having a diameter to the center of the wire of approximately 1⅝ inches and having approximately 7 turns. The hexagonal nut 246 is threaded onto the threaded rod 222 to adjust the length of the spring between the bearing washer 244 and the spring cap washer 240. For example, in the illustrated embodiment, the initial length is adjusted to approximately 4 inches. The hexagonal nut may be loosened to increase the length and thereby reduce the force provided by the compression spring or tightened to decrease the length and thereby increase the force provided by the compression spring. The compression spring does not determine the static position of the upper end of the vertical stud 134. As described in detail below, the compression spring and the other elements of the upper energy absorption assembly 220 absorb blast energy and reduce the likelihood of a catastrophic failure of the blast wall assembly 110.

In alternative embodiments (not shown), the compression spring 238 may be replaced by a suitable thickness of an elastic rubber flange to provide the compression force for absorbing blast energy.

In conventional wall structures, the upper end of each vertical stud is secured to the upper mounting track via screws through the side walls of the mounting track that engage the side walls of the vertical stud. As shown in FIG. 2, the upper end of each vertical stud 134 is secured to the upper mounting track 140 and the horizontal stud 142 via an upper stud attachment blast clip 250, which is illustrated in the cross-sectional end view of FIG. 4 and which is shown in more detail in FIG. 5 and in FIG. 14. In the illustrated embodiment, the upper stud attachment blast clip comprises a rectangular plate of 12 gauge steel having a thickness of approximately 0.104 inch. The plate has a width of approximately 3 inches and has a length of approximately 8 inches. The plate is formed into an L shape having a longer leg 252 in a vertical orientation with a length of approximately 5 inches and having a shorter leg 254 in a horizontal orientation with a length of approximately 3 inches. Each leg has a plurality of mounting holes 256 (e.g., 6 holes) that provide clearances for the shafts of a corresponding plurality of mounting fasteners 258 that secure the blast clips to the vertical stud and to the upper mounting track and the horizontal stud. For example, the mounting fasteners advantageously comprise self-tapping sheet metal screws, such as, for example, 5/16 inch screws having hexagonal heads. The vertical stud, the upper mounting track and the horizontal stud may advantageously include drilled pilot holes positioned in alignment with the clearance holes to reduce the effort of inserting the mounting fasteners. For example, a plurality of pilot holes 260 are shown in the joined horizontal stud and upper mounting channel in FIG. 20. In accordance with this configuration, the side walls of the upper mounting track and the horizontal stud are unobstructed so that the horizontal stud may move freely within the upper blast track as described above.

FIG. 3 illustrates an enlarged cross-sectional elevational view of a portion of the lower concrete footer 114, the bottom channel 150, and the lower ends of two vertical studs viewed in the direction of the lines 3-3 in FIG. 1.

As shown in FIG. 3, the lower end of each vertical stud 134 is secured to the lower mounting track 150 via a lower stud attachment blast clip 270, which is illustrated in the cross-sectional end view in FIG. 4 and which is shown in more detail in FIG. 6 and FIG. 15. The lower stud attachment blast clip also comprises steel and has a length, width and thickness similar to the length, width and thickness corresponding to the upper stud attachment blast clip 250. The lower stud attachment blast clip is formed into a longer vertical leg 272 and a shorter horizontal leg 274 having similar dimensions to the upper stud attachment blast clip. The lower stud attachment blast clip has a plurality of mounting holes 276 (e.g., 6 holes) in the longer vertical leg to provide clearance for the shafts of a corresponding plurality of mounting fasteners 278.

As shown in FIG. 15, an oval-shaped mounting hole 280 is formed in the horizontal leg 274 of the lower stud attachment blast clip 270. For example, in the illustrated embodiment, the mounting hole has a width of approximately ½ inch and has a semicircular arc at each end with a radius of ½ inch. The centers of the arcs are spaced apart by approximately 1 inch. As shown in FIGS. 3, 4 and 6, the lower stud attachment blast clip is secured to the lower end of the vertical stud and is positioned with the lower anchor bolt 122 substantially in the center of the oval-shaped mounting hole. The length of the mounting hole allows the lower stud attachment blast clip to move laterally with respect to the lower footer 114.

As shown in FIG. 22, the lower mounting channel 150 includes a plurality of oval-shaped mounting holes 290 having dimensions corresponding to the dimensions of the mounting hole 280 in the lower stud attachment blast clip 270. The mounting holes in the lower mounting channel are spaced apart by the selected spacing of the vertical studs 134 (e.g., 16 inches center-to-center in the illustrated embodiment). The lower mounting channel is positioned over the lower anchor bolts 122 first and then the lower stud attachment blast clips for the vertical studs are positioned over the lower anchor bolts.

The lower mounting channel 150 and the lower stud attachment blast clip 270 are secured to the lower anchor bolt by placing a lower blast absorption pad 300 on the lower anchor bolt above the lower leg 274 of the lower attachment blast clip as shown in FIGS. 3, 4 and 6. As illustrated in more detail in FIG. 16, the lower blast absorption pad advantageously comprises a block 302 of an elastomer, such as, for example, ethylene propylene diene monomer (EPDM) rubber. In the illustrated embodiment, the elastomer block has a rectangular cross section in the plan view (e.g., looking from the top) with a width of approximately 2 inches and a length of approximately 4 inches. The length is advantageously increased when a wider lower mounting channel is used for a thicker wall. The elastomer block has a thickness of approximately 1.25 inches and has a substantially rectangular face in the end elevational view. In the preferred embodiment, the lower corners of the rectangular face are chamfered to accommodate any reduction in the channel width caused by rounding or filleting at the intersections of the vertical walls and the base of the lower mounting channel.

The elastomer block 302 has a bore 304 that is centrally located through the rectangular upper surface and that extends vertically through the block. In the illustrated embodiment, the vertical bore has a diameter of approximately 9/16 inches to accommodate the diameter of the lower anchor bolt 122.

The elastomer block 302 further includes a plurality of horizontal bores 306 that extend through the block orthogonal to the vertical bore 304. For example, in the illustrated embodiment, the block includes four horizontal bores with two bores located on either side of the vertical bore. The horizontal bores advantageously have diameters of approximately ½ inch. The absence of the EPDM material in the horizontal bores reduces the force required to compress the elastomer bock.

As further shown in FIG. 16, the lower blast absorption pad further includes a rectangular metal plate 310 having rectangular dimensions in the plan view substantially similar to the rectangular dimensions of the upper surface of the elastomer block 302. The metal plate advantageously comprises 20 gauge steel having a thickness of approximately 0.0375 inch. The rectangular metal plate includes a central circular hole 312 having substantially the same diameter as the vertical bore 304 of the elastomer block.

As shown in the assembled view of the lower blast absorption pad 300 in FIG. 17, the rectangular metal plate 310 is bonded to the upper surface of the elastomer block 302 with the edges substantially in alignment with the edges of the elastomer block and with the central circular hole 312 substantially aligned with the vertical bore 304. The metal plate is advantageously bonded to the elastomer block using epoxy, glue or another suitable adhesive.

As shown in FIG. 6, for example, the lower blast absorption pad 300 is mounted in the lower mounting channel 150 with the lower anchor bolt 122 passing through the vertical hole 304 and the circular hole 312 and with the rectangular metal plate 310 facing upward. The lower blast absorption pad is secured to the lower anchor bolt by a standard washer 320 and a hexagonal nut 322. The nut is tightened onto the lower anchor bolt to partly compress the elastomer block 302 to provide sufficient pressure so that the lower mounting channel and the lower end of the vertical stud 134 do not move when ordinary pressure is applied to the inner or outer surface of the blast wall assembly 110.

The blast wall assembly 110 and the components described above form an integrated system that effectively absorbs blast energy. Unlike conventional systems, the components of the blast wall assembly function in a manner similar to highway “crumple zones” by absorbing the energy generated by the sudden impact of a blast wave on the exterior surface of the blast wall. The components of the blast wall assembly flex, move, compress, crush and bend before the full magnitude of the blast load is transmitted via the components to the fasteners used to secure the assembly to the structure. By absorbing the sudden impact of energy, the system greatly reduces the likelihood of component failure and fastener failure. Although the blast wall assembly may incur repairable damage, the blast wall assembly absorbs a substantial portion of the blast energy rather than imploding into the interior space of the structure. Thus, the blast wall assembly greatly enhances the safety of the building structure and the occupants of the building structure.

When a blast pressure wave first impacts the exterior blast board, the exterior blast board (the outer blast panel 132) resists penetration by objects, such as rocks and shrapnel, which may be hurled against the wall by the blast force. A portion of the energy of the blast wave is absorbed by flexural bending of the exterior blast board. The load applied to the exterior blast board by the blast pressure wave is transferred to the vertical wall studs 134. The exterior blast board also provides lateral bracing for the vertical studs, which helps prevent torsional failure of the light gauge vertical studs. The exterior blast board also serves as a substrate for a variety of exterior finish systems that may be applied to the cementitious wall board forming the outer face of the exterior blast board. Thus, from the outside, the blast wall assembly 110 may be configured to have the cosmetic appearance of a conventional wall.

The light gauge (e.g., 16 gauge) vertical wall studs 134 are flexible. Thus, when the load from the blast pressure wave is applied to the wall studs via the outer blast panel 132, the wall studs bend and deform and eventually stretch. The magnitude of deformation of the wall studs may exceed the yield strength of the wall studs and cause a portion of the deformation to be permanent. The bending, deformation and stretching of the studs absorbs additional blast energy.

As each vertical wall stud 134 deforms inward away from the blast force, the stud has a tendency to pull out of the upper mounting channel 140 and the lower mounting channel 150 that constrain the upper end and the lower end, respectively, of each stud. The angle clip (the upper stud attachment blast clip 250) at the top of each vertical stud and the angle clip (the lower stud attachment blast clip 270) at the bottom of each stud resist this pull-out force. In particular, the top angle clip and the bottom angle clip for each stud resist disengagement of the stud from the upper mounting channel and the lower mounting channel while simultaneously absorbing blast energy. As the vertical stud deflects inwardly, the chord distance between the top end and the bottom end of the stud shortens. The horizontal legs 254, 274 of the angle clips deform by bending in response to the tensile force that attempts to straighten the angle clips. The deformations of the angle clips absorb additional blast energy.

When the bottom angle clip (the lower stud attachment blast clip 270) deforms, the tendency of the bottom angle clip to straighten is resisted by the bottom energy absorbing pad 300. The bottom energy absorbing pad is compressed vertically as the horizontal leg 274 attempts to pull away from the lower mounting channel 150. The compression of the bottom energy absorbing pad absorbs additional blast energy. The metal plate 310 laminated to the top of the bottom energy absorbing pad helps prevent the pad from pulling over an anchor bolt 120 at the bottom of the wall and prevents the pad from being crushed by the hexagonal nut 322 that secures the pad to the bottom attachment anchor bolt.

The bottom energy absorbing pads 300 at the bottoms of the wall studs also absorb energy while allowing the entire base of the wall to move inward away from the blast. As described above, the bottom mounting channel (or track) 150 and the bottom clips (the lower stud attachment blast clip 270) include respective slots (or oversized holes) 290, 280 that permit the entire lower portion of the blast wall assembly 110 to move inward away from the blast force until reaching the end of the slot or the boundary of the oversized hole. The bottom energy absorbing pads prevent the wall from moving too quickly and applying a shock load to the lower anchor bolts 120. When the bottom energy absorbing pads compress under load, the pads create a more gradual (cushioned) increase in the load to the wall anchors. Thus, the bottom energy absorbing pads help preserve the integrity of the critical attachment of the wall to the building structure.

The upper mounting system 200 and the upper energy absorbing assembly 220 at the top of the blast wall assembly 110 absorb blast energy and resist destructive movement caused by the blast energy. The upper mounting system and the upper energy absorbing assembly also permit the floor above the blast wall assembly to deflect vertically in response to changing live loads to the floor above the wall, the floor below the wall or both. The floating configuration of the upper mounting allows deflections to occur without transferring axial loads (e.g., bearing loads) to the wall. The blast wall assembly disclosed herein can be used as either a non-bearing partition wall or as a curtain wall.

When a top angle clip (the upper stud attachment blast clip 250) deforms, the tendency of the clip to straighten is reduced by the bending of the horizontal flange stud 142 that spans the approximately 24-inch spacing between adjacent upper mounting systems 200. The tensile force caused by a blast causes the angle clip to bend (e.g., straighten) and induces weak axis bending in the horizontal flange stud. The horizontal flange stud also provides an engagement between the vertical wall studs and the upper blast track 144. In particular, the outer surfaces of the vertical walls of the horizontal flange stud ride may float up or down within the cavity formed by the upper blast track. The floating engagement between the horizontal stud and the upper blast track is configured to reduce the effect of the blast forces. As described above, the top angle clip and the horizontal flange stud are nested so that the side walls of the horizontal flange stud are unobstructed within the upper blast track to thereby accommodate vertical movement between the floor above and the wall below. Additional blast energy is absorbed by bending of the horizontal stud flange and bending of the flange of the upper blast track on the side of the wall opposite the blast. Both components bend in a direction normal to the plane of the wall.

Lateral movement of the blast wall assembly 110 in a direction normal to the wall plane is primarily resisted by bending of a down-turned flange of the upper blast track 144. As each vertical stud 134 bends, the chord distance between the upper and lower ends of the vertical stud shortens as discussed above. The spring 238 or other elastic member in the upper energy absorption assembly 220 compresses to absorb blast energy. Once the spring in the energy absorbing assembly is fully compressed, the threaded steel rod 222 in the assembly transmits tensile loads to the upper blast track through the anchor wedge washer 224 described above. As the wall deforms inward, the threaded rod pivots to transfer tensile load and shear load to the upper blast track, which causes the upper blast track to deform in the vicinity of the wedge washer. The deformation of the upper blast track absorbs more blast energy.

Once the blast load is transferred to the upper blast track 144 by bending the outer wall (the flange of the upper blast track) and by the upper energy absorption assembly 220, the transferred load is transferred to the building structure by way of the upper anchor bolt 120 embedded in the concrete header 112. The force transferred to the upper anchor bolt is cushioned by the deformation of the trapezoidal channel (the depressed portion 146) in the upper blast track and by the vertical flange and weak axis bending of the U-shaped blast track anchor channel 202. The shape of the blast track in combination with the blast track anchor channel results in a more gradual transfer of forces to the top connection, which helps preserve the integrity of the top connection and of the blast wall assembly 110.

The blast wall assembly further comprises an interior blast board (the inner blast panels 130). Each panel of the interior blast board comprises a layer of metal 160 and an interior finish wall board 162 to form a generally rectangular sheet. In the illustrated embodiment, the interior blast board is fabricated with a metal flange 164 extending along one of the long edges. The long edges are oriented horizontally in the preferred embodiments. The metal flange allows the interior sheathing to be spliced to the adjacent sheathing (the inner blast panel immediately above). The splice effectively connects the upper and lower sheathing boards to form a continuous protective curtain reaching from the top to the bottom of the wall. If one or more sheets become dislodged, the dislodged sheets remain in place on the wall and pose no hazard to the building occupants. Preferably, the sheets are positioned on the wall with the locations of the splices staggered so that the splices do not coincide with the utility punch outs in the vertical studs of the wall. Thus, the interior blast board reinforces the wall and helps prevent stud failure at the utility punch-outs. Furthermore, the metal lined interior blast boards provide torsional restraint for the vertical studs 134 to effectively prevent torsional failure of the vertical studs. In alternative embodiments, the panels of the interior blast wall are mounted with the long edges oriented vertically. In the vertically oriented embodiment, the panels can be manufactured without the metal flange along the long edge since the seams between panels will be on a vertical stud.

FIG. 24 illustrates a perspective view of portion of a wall section 500 in accordance with a further embodiment of an energy absorbing blast wall positioned between the upper header 112 and the lower footer 114. FIG. 25 illustrates an enlarged cross-sectional plan view of the portion of the wall section in FIG. 24 viewed in the direction of the lines 25-25 in FIG. 24. As shown in FIG. 25, a plurality of cavities 510 formed between inner blast panels 512 and outer blast panels 514, which are mounted on a plurality of C-studs 516. The inner and outer blast panels are preferably constructed as described above with respect to FIGS. 8 and 9.

In FIGS. 24 and 25, the C-studs 516 in the wall section 500 are mounted in a conventional manner with the main body portions (webs) 520 of the C-studs perpendicular to the inner blast panels 512 and the outer blast panels. The blast panels are mounted to the opposing side walls (main flanges) 522 of the C-studs. The thickness of the cavity formed between the inner and outer blast panels is determined by the length of the webs of the C-studs and can vary from 3.5 inches to 10.5 inches in accordance with a selected overall thickness of the wall section. The center-to-center spacing between adjacent C-studs is advantageously selected to be 16 inches; however, the spacing can be modified if desired. For example, as discussed above, the C-studs can be spaced apart by 12 inches for greater blast strength. The wall section illustrated in FIGS. 24 and 25 advantageously has a width of approximately 48 inches, a height of approximately 96 inches and thickness of approximately 6 inches. With the illustrated 16-inch center-to-center spacing, three cavities are formed in the wall section. The blast panels may be mounted on the studs with the long edges oriented horizontally as described above in order to interconnect adjacent wall sections (not shown). However, in the embodiments illustrated in FIGS. 24-35, at least one, and preferably both, of the inner and outer blast panels are mounted on the C-studs with the long edges of the blast panels oriented vertically. In such embodiments, the blast panels are preferably mounted so that the seams between adjacent blast panels are aligned with one of the two middle C-studs (when the spacing is 16 inches) rather than being aligned with the seams joint between adjacent wall sections so that the blast panels span the abutted joint between adjacent wall sections. By staggering the blast panels with respect to the wall sections in the alternative embodiment, the blast panels assist in interconnecting adjacent wall sections. As further illustrated in FIG. 25, the vertical seam 526 between adjacent inner blast panels and the vertical seam 528 between adjacent outer blast panels are staggered with respect to each other.

Each of the cavities 510 in the wall section 500 is substantially filled with an energy absorbing material 530 that also serves as an insulating material. For example, in an exemplary embodiment, the energy absorbing material advantageously comprises expanded polystyrene (EPS) foam. The energy absorbing material may be added during the erection of the wall section by filling each cavity with heated, flowable material and allowing the material to cool to a solid form. In certain preferred embodiments, the energy absorbing material and the C-studs 516 are formed by mass production techniques (e.g., in a factory) with the foam adhered to the C-studs using a heat-reactive adhesive. After erecting the factory-built panel section with the C-studs positioned between an upper track assembly 540 and a lower track assembly 542, as described above, the inner blast panels 512 and the outer blast panels 514 are secured to the flanges 522 of the C-studs, as described above. As shown in FIG. 25, the C-stud at each end of the wall section is mounted flush with the edge of the wall section. Furthermore, a C-stud at one end of the wall section is mounted in the opposite orientation to the other C-studs. This configuration allows each wall section to fully enclose the cavities. In this configuration, adjacent wall sections are mounted with main body portions of the end C-studs of each wall section back-to-back with the main body portions of the end C-studs of adjacent wall sections.

In FIG. 24, the upper track assembly 540 and the lower track assembly 542 are mounted to the upper header 112 and the lower footer 114, respectively, and are constructed as described above to provide the advantageous energy absorbing characteristics also described above. A portion of the energy absorbing material 530 filling the cavities is removed to provide clearance for the components that extend into the cavities from the upper track and the lower track. In embodiments where the energy absorbing material is added at the construction site, the components extending into the cavities can be shrouded during the filling process.

In a further embodiment illustrated in FIGS. 26 and 27, a wall section 600 is constructed as described above in connection with FIGS. 24 and 25; however, the C-studs 516 in FIGS. 26 and 27 are mounted to a conventional fixed upper track assembly 610 and a conventional fixed lower track assembly 612, which are mounted directly to the upper header 112 and the lower footer 114, respectively.

FIG. 28 illustrates a perspective view of portion of a wall section 700 in accordance with a further embodiment of an energy absorbing blast wall. FIG. 29 illustrates an enlarged cross-sectional plan view of the portion of the wall section in FIG. 28 viewed in the direction of the lines 29-29 in FIG. 28. The embodiment of FIGS. 28 and 29 is similar to the embodiment of FIGS. 24 and 25; however, as shown in FIG. 29, a single cavity 710 is formed between inner blast panels 712 and outer blast panels 714. As described above, the inner and outer blast panels are preferably mounted with the long edges in a vertical orientation, with a respective vertical seam 716 between adjacent inner blast panels and a respective vertical seam 718 between adjacent outer blast panels. As shown in FIG. 29, the vertical seam between outer blast panels is staggered with respect to the vertical seam between inner blast panels. Neither vertical seam coincides with a joint between adjacent wall sections so that the inner and outer blast panels span between and thereby interconnect adjacent wall sections. Unlike the previously described embodiment, the inner blast panels and the outer blast panels are mounted on the main body portions (webs) 724 of a first plurality 720 of U-channel studs and a second plurality 722 of U-channel studs, respectively. The side walls (flanges) 726 of the U-channel studs extend into the cavity perpendicular to the respective blast panels. Thus, the side walls are embedded in the energy absorbing material 730 that fills the cavity between the inner and outer blast panels.

As illustrated in FIG. 29, the first plurality 720 and the second plurality 722 of U-channel studs are spaced apart by a selected distance to provide a selected thickness for the cavity 710 between the inner blast panels 712 and the outer blast panels 714. For example, the thickness may vary from 3.5 inches to 10.5 inches in certain embodiments. The thickness of the cavity and thus the spacing between the inner and outer blast panels is determined by the thickness of the energy absorbing material 730 that fills the cavity. Preferably, the U-channel studs and the energy absorbing material are formed in mold or template in a factory setting so that the thickness is readily controllable to a desired specification. As described above, the energy absorbing material may be any energy absorbing material and is advantageously expanded polystyrene (EPS) foam in certain embodiments.

As further illustrated in FIG. 29, the first plurality 720 of U-channel studs is offset from the second plurality 722 of U-channel studs by approximately 1 inch in the horizontal direction. The energy absorbing material 730 is shaped so that the portion of the material proximate the first plurality of U-channel studs and the inner blast panels 712 is offset by a corresponding amount so that the energy absorbing material extends between respective outermost sidewalls 726 of the first plurality of U-channel studs. Similarly, the portion of the material proximate the second plurality of U-channel studs and the outer blast panels 714 is offset by a corresponding amount so that the energy absorbing material extends between respective outermost sidewalls of the second plurality of U-channel studs. As a result of the offsets, at one end of the energy absorbing material, a portion 740 proximate the inner blast panels extends farther than a portion 742 proximate the outer blast panels. At the other end of the energy absorbing material, a portion 750 proximate the outer blast panels extends farther than a portion 752 proximate to the inner blast panels. Preferably, the two portions of the energy absorbing material are divided substantially equally along a horizontal centerline 760 so that the two portions have substantially the same thickness. Accordingly, when two wall sections are abutted, the extended portions of the energy absorbing material of one wall section are juxtaposed with the unextended portions of the energy absorbing material of the other wall section so that adjacent wall sections form a shiplap structure. Furthermore, each wall structure is rotationally symmetric such that each section of energy absorbing material with the embedded U-channel studs may be installed with either surface facing either the inner blast walls or the outer blast walls.

The wall section 700 of FIGS. 28 and 29 with the U-channel studs 720, 722 and the shiplap cavity structure 730 may be installed with the upper energy absorbing track assembly 540 and the lower energy absorbing track assembly 542 as described above. Alternatively, as shown in FIGS. 30 and 31, a wall section 750 with the U-channel studs and the shiplap cavity structure may be installed in combination with the fixed upper track 610 and the fixed lower track 612.

FIGS. 32 and 33 illustrate a wall section 800 similar to the embodiment of FIGS. 28 and 29; however, in FIGS. 32 and 33, a cavity 810 is formed between inner blast panels 812 and outer blast panels 814, which are mounted on a first plurality 820 of C-studs and a second plurality 822 of C-studs, respectively. The C-studs in FIGS. 32 and 33 replace the corresponding U-channel studs in FIGS. 28 and 29. As described above, each C-stud comprises a main body portion (web) 824, opposing side walls (main flanges) 826 and smaller flanges (lips) 828, which are perpendicular to the side walls. The cavity between the inner and outer blast panels is filled with energy absorbing material 830, as described above. The C-studs are mounted with their respective main body portions against the respective blast panels. The side walls (main flanges) of the C-studs extend into the energy absorbing material and the smaller flanges (lips) of the C-studs extend further into the energy absorbing material perpendicular to the side walls to provide additional engagement between the C-studs and the energy absorbing material. The C-studs on opposing sides of the energy absorbing material are offset horizontally as described above, and the energy absorbing material is formed with the shiplap structure, described above in connection with FIGS. 28 and 29. As described above, the inner and outer blast panels are preferably mounted with the long edges in a vertical orientation, with a respective vertical seam 840 between adjacent inner blast panels and a respective vertical seam 842 between adjacent outer blast panels. As shown in FIG. 33, the vertical seam between outer blast panels is staggered with respect to the vertical seam between inner blast panels. Neither vertical seam coincides with a joint between adjacent wall sections so that the inner and outer blast panels span between and thereby interconnect adjacent wall sections.

In FIGS. 32 and 33, the wall section 800 is mounted between the upper energy absorbing track assembly 540 and the lower energy absorbing track assembly 542. FIGS. 34 and 35 illustrate the corresponding wall structure 850 mounted between the fixed upper track assembly 610 and the fixed lower track assembly 612.

In the above-described embodiments, the blast wall sections are installed between an upper header 112 and a lower footer 114. In alternative embodiments, the blast wall sections can also be installed as curtain walls which hang on the outside of the building structure and span across the floors. FIG. 36 illustrates the wall section 850 of FIG. 34 installed as a portion of a curtain wall that spans from an upper beam 870 to a lower beam 872. Rather than being mounted between the two beams, the wall section is mounted to the outer face of each beam as shown using suitable mounting hardware (not shown). The other wall sections disclosed herein can be similarly adapted to be installed as sections of a curtain wall.

FIG. 37 illustrates a cross-sectional view of an alternative wall section 900, which is similar to the wall sections illustrated in the cross-sectional views of FIGS. 33 and 35; however, in FIG. 37 the C-studs are replaced with a modified set of studs comprising a plurality of double-lipped (hat channel) studs 910 and a plurality of single-lipped studs 912. In particular each of the double-lipped studs has a respective web 920 and first and second outer flanges 922 perpendicular to the web. Each of the outer flanges has a respective lip 924 perpendicular to the respective flange and facing outward (away from the center of the stud) from the respective flange. In an illustrated embodiment, the web of the stud has a width of approximately 4 inches, each outer flange has a length of approximately 1.5 inches, and each lip has a length of approximately 1 inch. Each stud advantageously comprises galvanized steel having a thickness in a range corresponding to a range from 18 gauge to 12 gauge.

The single-lipped studs 912 are similar to the double-lipped studs 910. Each single-lipped stud has a respective web 930 and first lipped outer flange 932 and a second unlipped outer flange 934 oriented perpendicularly to the web. The lipped outer flange has a lip 936 which is directed outwardly (away from the center of the stud) as described above for the double-lipped stud. The unlipped outer flange) does not have a lip.

As shown in FIG. 37, a respective one of the single-lipped studs 912 is positioned at each end of the wall section 900 with the unlipped outer flange 934 aligned with the respective end of formed energy absorbing material 940 between an inner blast panel 942 and an outer blast panel 944. The respective web 930 of each single-lipped stud is positioned against the respective blast panel with the unlipped flange and the lipped flange 932 extending into the energy absorbing material. The single lip 936 extends from the lipped flange into the energy absorbing material.

The double-lipped studs 910 are positioned with their respective webs 920 positioned against one of the inner blast panel 942 or the outer blast panel 944. Each double-lipped stud is positioned with the respect to the single-lipped studs 912 so that the center of each double-lipped stud is approximately 16 inches from the unlipped outer flange 934 of the adjacent single-lipped stud at the nearest end of the wall section. Accordingly, for a wall section 900 having a nominal width of 48 inches, two double-lipped studs are disposed between each single-lipped stud. The width of the wall section and the spacing between studs can be varied for different applications. The spacing between the inner blast panel and the outer blast panel can also be varied in accordance with a desired wall thickness.

In FIG. 37, the energy absorbing material 940 between the inner blast panel 942 and the outer blast panel 944 is formed with the offsets at each end to form the shiplap shape described above. Accordingly, the studs adjacent the inner blast panel are staggered with respect to the studs adjacent the outer blast panel, as described above.

FIG. 38 illustrates a further embodiment of a wall section 950, which is similar to the wall section 900 in FIG. 37. Accordingly, like elements are numbered as in FIG. 37. As discussed above, the energy absorbing material 940 in the wall section of FIG. 37 is formed with a shiplap configuration. The wall section of FIG. 38 includes energy absorbing material 960 that does not include the offset between the portion adjacent an inner blast panel 962 and an outer blast panel 964. Accordingly, the unlipped outer flanges 934 of the single-lipped studs 912 at each edge of the wall section are aligned rather than being staggered. Similarly, the double-lipped studs 910 adjacent the inner blast panel are aligned with corresponding double-lipped studs adjacent the outer blast panel.

The embodiments of FIGS. 37 and 38 are advantageous in providing additional surface area of the studs 910, 912 in contact with the energy absorbing material 940, 960 to provide increased adhesion between the studs and the energy absorbing material.

In FIGS. 37 and 38, one or both of the respective inner blast panels 942, 962 and the respective outer blast panels may be installed with the respective long edges of the panels oriented horizontally or oriented vertically, as discussed above.

FIG. 39 illustrates a perspective view of a blast wall 1000 similar to the blast wall 100 of FIG. 1 but with a lower track (channel) 1010 having integral tabs 1012 for connecting to the vertical studs 134. FIG. 40 illustrates an enlarged perspective view of a portion of the lower track and the vertical stud at the location of the tab. As shown in FIG. 40, the tab extends substantially perpendicularly from the webbing 1014 of the lower track. Preferably, the tab includes a pilot hole 1016 (see FIG. 44) into which a sheet metal screw 1020 is inserted and then rotated to engage the lower end of the webbing 1030 of the vertical stud positioned adjacent to the tab. The tab replaces the lower stud attachment blast clip 270 shown in FIG. 3. In a further embodiment (not shown), each upper stud attachment blast clip 250 can also be replaced by a corresponding tab (not shown) formed in the upper track in the manner described below. The lower track in FIGS. 39 and 40 is advantageously used in combination with the lower blast absorption pad 300 (shown in phantom in FIG. 40); however, each lower anchor bolt 122 passes only through the blast absorption pad and a mounting hole 1032 in the webbing of the channel. In the illustrated embodiment, the mounting holes are round. The mounting holes may also be oval-shaped as described above in connection with the embodiment shown in FIG. 22.

In one embodiment of the lower track 1010 in accordance with FIGS. 39 and 40, each tab 1012 and pilot hole 1016 are formed in the webbing 1014 during the manufacturing of the track by stamping or other suitable process. In particular, a generally U-shaped slot 1040 is formed in the webbing along with the pilot hole as shown in FIGS. 41 and 42. The mounting holes 1032 may be formed in the webbing during the same process. The slots are spaced apart by the desired spacing of the vertical studs 134 (e.g., 16 inches) and are displaced from the slots by a selected distance. The mounting holes can be spaced apart by similar distances as shown in FIG. 41; however, in the illustrated embodiment the anchor bolts 122 and blast absorption pads 300 are not used to secure the vertical studs to the webbing. Thus, it is not necessary to insert an anchor bolt and a blast absorption pad at the location of each mounting hole.

FIG. 43 illustrates a perspective view of the second stage of construction of the lower track 1010 of FIG. 41 showing the tabs 1012 bent upward from the webbing 1014 to a position substantially perpendicular to the webbing. FIG. 44 illustrates an enlarged perspective view one of the tabs.

The embodiment of FIGS. 39-44 advantageously provides additional blast protection by interconnecting the webbing 1030 of each vertical stud 134 with the webbing 1014 of the lower track 1010 without requiring the additional hardware of the lower stud attachment blast clip 270 for each stud. As discussed above, the upper stud attachment blast clips 250 may also be replaced by forming corresponding tabs in an upper track (not shown).

FIG. 45 illustrates a perspective view of a blast wall 1100 similar to the blast wall 100 of FIG. 1 but with a lower track 1110 having a lower stud attachment clip 1112 attached to the webbing 1114 of the vertical stud 134 and also attached directly to the webbing 1116 of the lower track. FIG. 46 illustrates an enlarged perspective view of a portion of the lower track and the vertical stud proximate to the location of the intersection of the stud with the lower track.

As illustrated in FIGS. 45 and 46, the lower stud attachment clip 1112 is mounted to the webbing 1114 of the stud 134 as described above using a plurality of self-tapping screws 1120. For example, the lower stud attachment clip is advantageously mounted to the stud prior to installation with the stud lying horizontally so that the screws do not have to be driven horizontally by the installer when the stud is in a vertical position. After positioning the stud, the horizontal leg of the lower stud attachment clip is secured to the webbing 1116 of the lower track 1110 by a plurality of screws 1122, as illustrated, or by welding the horizontal leg to the webbing, or by attaching the horizontal leg to the webbing using power-driven pins. When screws or pins are used, the screws or pins are also driven into the concrete of the underlying lower footer 114.

As further illustrated in FIGS. 45 and 46, the lower track 1110 is secured to the lower footer 114 using the anchor bolts 122 as before; however, in the embodiment of FIGS. 45 and 46, a steel plate 1130 is positioned beneath the washer 320 and nut 322 so that when the nut is tightened on the anchor bolt, the steel plate secures the webbing 1116 of the lower track against the lower footer. In the illustrated embodiment, the steel plate is flat and is generally rectangular. The rectangular dimensions of approximately 4 inches by 2 inches for a 4-inch lower track so that the steel plate fits within the lower track. The steel plate advantageously has a thickness of approximately 0.25 inch. During a blast event, the steel plate at each anchor bolt protects the relatively thin webbing of the lower track from stresses caused by forces that would otherwise bend the webbing in the locations of the anchor bolts. Unlike the embodiment of FIG. 1, the embodiment of FIGS. 45 and 46 advantageously allows the installer to position the studs 134 independently of the locations of the anchor bolts to provide additional flexibility in selecting positions for the studs and the anchor bolts.

One skilled in art will appreciate that the foregoing embodiments are illustrative of the present invention. The present invention can be advantageously incorporated into alternative embodiments while remaining within the spirit and scope of the present invention, as defined by the appended claims. 

1. A wall system for protecting a building structure from pressure caused by explosive blasts, comprising: a plurality of vertical studs having respective upper ends and lower ends; at least one outer blast wall panel secured to the vertical studs to form an outer wall of the wall system; at least one inner blast wall panel secured to the vertical studs to form an inner wall of the wall system; an upper mounting system attached to the building structure, the upper ends of the vertical studs attached to the upper mounting system; a lower mounting system attached to the building structure, the lower ends of the vertical studs attached to the lower mounting system; at least one cavity formed between the at least one outer blast wall and the at least one inner blast wall; and an energy absorbing material that substantially fills the at least one cavity.
 2. The wall system as defined in claim 1, wherein each vertical stud extends from the at least one outer blast wall panel to the at least one inner wall panel.
 3. The wall system as defined in claim 1, wherein each vertical stud is positioned to be attached to only the at least one inner blast wall panel or to only the at least one outer blast wall panel.
 4. The wall system as defined in claim 3, wherein: the vertical stud attached to the at least one inner blast wall panel comprises a U-channel stud having a web and a respective flange at each edge of the web; and the at least one inner blast wall panel is connected to the web of the vertical stud with the flange at each edge of the web extending into the energy absorbing material in the cavity.
 5. The wall system as defined in claim 3, wherein: the vertical stud attached to the at least one outer blast wall panel comprises a U-channel stud having a web and a respective flange at each edge of the web; and the at least one outer blast wall panel is connected to the web of the vertical stud with the flange at each edge of the web extending into the energy absorbing material in the cavity.
 6. The wall system as defined in claim 3, wherein: the vertical stud attached to the at least one inner blast wall panel comprises a C-stud having a web, a respective flange at each edge of the web, and a respective lip perpendicular to each flange; and the at least one inner blast wall panel is connected to the web of the vertical stud with the flange at each edge of the web extending into the energy absorbing material in the cavity, and with each lip embedded in the energy absorbing material.
 7. The wall system as defined in claim 3, wherein: the vertical stud attached to the at least one inner blast wall panel comprises a C-stud having a web, a respective flange at each edge of the web, and a respective lip perpendicular to each flange; and the at least one inner blast wall panel is connected to the web of the vertical stud with the flange at each edge of the web extending into the energy absorbing material in the cavity, and with each lip embedded in the energy absorbing material.
 8. The wall system as defined in claim 1, wherein the energy absorbing material comprises expanded polystyrene foam.
 9. A wall system for protecting a building structure from pressure caused by explosive blasts, comprising: an inner blast wall panel comprising a generally rectangular metal sheet and an interior wall board laminated to the metal sheet, the inner blast wall panel secured to vertical studs with the metal sheet positioned against the vertical studs and with the interior wall board facing away from the vertical studs; an outer blast wall panel comprising a generally rectangular metal sheet and an exterior wall board laminated to the metal sheet, the outer blast wall panel secured to vertical studs with the metal sheet positioned against the vertical studs and with the exterior wall board facing away from the vertical studs; and an energy absorbing material positioned between the inner blast panel and the outer blast panel.
 10. The wall system as defined in claim 9, wherein the wall system is mounted between an upper header and a lower footer.
 11. The wall system as defined in claim 9, wherein the wall system is mounted to an outer face of a structure to span between two floors of the structure.
 12. The wall system as defined in claim 9, wherein the inner blast panel and the outer blast panel are secured to opposing flanges of studs that extend through the energy absorbing material between the inner blast panel and the outer blast panel.
 13. The wall system as defined in claim 9, wherein the inner blast panel is secured to a first set of studs, and the outer blast panel is secured to a second set of studs, the first set of a studs and the second set of studs separated by the energy absorbing material.
 14. A wall system for protecting a building structure from pressure caused by explosive blasts, comprising: a plurality of vertical studs having respective upper ends and lower ends; at least one outer blast wall panel secured to respective outer sides of the vertical studs; at least one inner blast wall panel secured to respective inner sides of the vertical studs; an upper mounting system attached to the building structure, the upper mounting system including a fixed track, a movable mounting track, and an energy absorbing system that flexibly couples the movable mounting track to the fixed track, the upper ends of the vertical studs attached to movable mounting track; and a lower mounting system comprising a mounting track that aligns the lower ends of the vertical studs and a attachment device for each vertical stud that resists vertical and lateral movement of lower end of the respective vertical stud.
 15. The wall system as defined in claim 14, wherein the mounting track of the lower mounting system comprises a lower track having a webbing and opposing flanges, and wherein the attachment device comprises a tab formed by a portion of the webbing bent perpendicular to the webbing.
 16. The wall system as defined in claim 14, wherein the mounting track of the lower mounting system comprises a lower track having a webbing, and wherein the respective attachment device for each vertical stud comprises a respective L-shaped attachment clip that secures each vertical stud to the webbing of the lower track and further comprises a plurality of plates that secure the webbing of the lower track to a corresponding plurality of anchor bolts to secure the lower track to a lower footing into which the anchor bolts are embedded. 